The present invention relates generally to an apparatus for decorating articles and more particularly to an improved apparatus for applying heat-transfer labels onto objects.
Heat-transfer labels are well known in the art and are commonly applied onto objects, such as bottles, containers or other similar articles, to identify the particular product contained within the object.
Heat-transfer label assemblies are well known and widely used in the art. Heat-transfer label assemblies are typically manufactured as a continuous roll and commonly comprise a label-carrying continuous web (also commonly referred to simply as a carrier web), such as a polyethylene coated paper sheet, a release layer (also commonly referred to as a release mechanism), such as a wax release layer, affixed onto a surface of the carrier web and a heat-transfer label (also commonly referred to simply as a label), which is disposed on the wax release layer. The heat-transfer label typically comprises a protective layer affixed onto the wax release layer, an ink design layer affixed onto the protective layer and an adhesive layer affixed onto the ink design layer.
In U.S. Pat. No. 5,824,176 to S. H. Stein et al., which is hereby incorporated by reference, there is disclosed a composition for use in forming an adhesive layer and a heat-transfer label including such an adhesive layer. In one embodiment, the label is designed for use on silane-treated glass containers of the type that are subjected to pasteurization conditions. The label includes a support portion and a transfer portion, the transfer portion being positioned over the support portion. The support portion includes a sheet of paper overcoated with a release layer of polyethylene. The transfer portion includes an organic solvent-soluble phenoxy protective lacquer layer, an organic solvent-soluble polyester ink layer over the protective lacquer layer, and an acrylic adhesive layer over the ink layer. The adhesive layer is formed by depositing onto the ink layer, e.g., by gravure printing, a composition comprising a water-based acrylic resin dispersion or emulsion, isopropyl alcohol and water, and then evaporating the volatile components of the composition to leave an acrylic film.
Heat-transfer label decorators are well known and are commonly used in the art to apply heat-transfer labels onto objects.
Heat-transfer label decorators, also commonly referred to as decorator systems or decorators, typically comprise a turret for sequentially positioning the object at various application stations, a label transfer system for transferring a heat-transfer label from the continuous carrier web onto the desired article at a transfer station, a web transport assembly for sequentially positioning the labels on the carrier web at the transfer station and conveyors for feeding articles into the turret before labeling and for removing articles from the turret after labeling.
In use, heat-transfer label decorators typically function in the following manner. First, the web transport assembly disposes a portion of the supply roll of the heat-transfer label assembly against a preheating device, commonly in the form of an elongated, heated, metal platen. Disposing the heat-transfer label assembly against the preheating device causes the wax release layer to begin to melt and soften, thereby creating a weakened adhesion between the heat-transfer label and the paper sheet carrier web. After preheating a portion of the heat-transfer label assembly, the web transport assembly disposes the preheated heat-transfer label assembly against a label transfer system, commonly in the form of a heated rubber roller, the web transport assembly being synchronized with the turret so that a heat-transfer label from the preheated heat-transfer label assembly is positioned between the label transfer system and the article to be labeled. With the label positioned as such, the label transfer system further subjects the preheated heat-transfer label assembly to heat and presses the adhesive layer of the heat-transfer label into contact with the object. As the heat-transfer label assembly is subject to additional heat by the label transfer system, the wax layer continues to soften and melt and the adhesive layer becomes tacky, thereby allowing the heat-transfer label to transfer from the paper sheet carrier web and onto the desired object.
One type of heat transfer label decorator which is well known in the art is a continuous heat-transfer label decorator. A continuous heat-transfer label decorator is capable of decorating a continuous supply of objects at a variety of different speeds. As an example, a continuous heat-transfer label decorator is able to decorate a continuous supply of objects at a moderate, or normal, speed (approximately 50 containers per minute). As another example, a continuous heat-transfer label decorator is able to decorate a continuous supply of objects at a high speed (approximately 400 containers per minute). As can be appreciated, the turret of a continuous decorator advances a continuous supply of objects to the label transfer system for decoration without intermittently reducing the speed of the advancement of the object during the decoration process.
In U.S. Pat. No. 5,650,037 to M. G. Larson, there is disclosed a continuous, high speed, thermal ink transfer decorating apparatus, also commonly referred to as a heat transfer label decorator in the art. In the thermal ink transfer machine, the web is drawn translationally through a station at which thermal ink graphics are transferred from the web to the periphery of a container such as a glass or plastic bottle or can. Transfer of the graphics is effected with a transfer head or cylinder which has arranged about its axis of rotation a plurality of equally spaced apart radially spring biased rollers. When the longitudinally extending graphics on the web enters the transfer station, the spring biased rollers yield radially inwardly and outwardly to press against the backside of the web to effect transfer of the graphics. The apparatus has the rotating transfer head on one side of the web and the containers carried on a turntable on the opposite side of the web. The transfer head rotates in a particular direction around its vertical axis and drives the rollers orbitally toward and away from the graphics transfer station. The containers are supported on rotationally driven disks that are equally spaced apart on the turntable and bring the periphery of the containers into alignment with one of the spring biased rollers when graphics transfer is initiated where the leading end of the graphics make first contact with the container. The containers rotate in a direction opposite from the direction in which the turntable rotates. Thus the periphery of a container when in the transfer station moves in the same direction as the web. Means are provided for feeding web from an unwind reel to the transfer station and from the transfer station to a rewind reel. Means are also provided for maintaining equality in the length of web extending from the unwind reel to the transfer station and from the transfer station to the rewind reel. Means are also provided for maintaining constant tension in the web.
It has been found that continuous decorating apparati, such as the continuous, high speed, decorating apparatus described in U.S. Pat. No. 5,650,037 to M. G. Larson, experience notable advantages. First, the continuous advancement of the objects to be decorated creates a continuous chain of decoration. As a consequence, a relatively large number of objects can be decorated in a relatively short period of time (i.e., approximately 400 objects can be decorated per minute in high speed applications), thereby improving the overall productivity and efficiency of the apparatus.
Although well known and widely used in the art, continuous decorating apparati, such as of the type described in U.S. Pat. No. 5,650,037 to M. G. Larson, typically suffer from a notable drawback. Specifically, due to the continuous advancement of the objects during the decoration process, each object has a relatively short period of time in which the label transfer system disposes the heat-transfer label into contact thereto. In addition, in order to transfer a label around the entire periphery of an object, the object must be quickly rotated 360 degrees within the short period of decoration. Furthermore, because the advancement speed of the supply roll must always equal the rotational speed of the object, the supply roll of the heat-transfer label assembly must also be advanced at the same rapid rate in which the object rotates in order to enable the label to be transferred onto the desired object within the short period of contact. Accordingly, because the heat-transfer label assembly is fed at a relatively high rate, the duration of time in which the heat-transfer label assembly is subjected to the heat of the platen and the heat transfer system is significantly limited. As a result, it has been found that the heat-transfer label assembly is often inadequately heated, thereby precluding effective transfer of the heat-transfer label onto the desired object, which is highly undesirable.
It is an object of the present invention to provide a novel apparatus for applying heat-transfer labels onto objects.
It is another object of the present invention to provide an apparatus as described above which decorates a continuous supply of objects.
It is yet another object of the present invention to provide an apparatus as described above which effectively applies heat-transfer labels onto objects.
It is still another object of the present invention to provide an apparatus as described above which requires a limited number of parts, which is easy to use and which is inexpensive to manufacture.
Accordingly, there is provided an apparatus for applying the heat-transfer label of a heat-transfer label assembly onto an object, said apparatus comprising a decorating unit for applying the heat-transfer label onto the object during a period of decoration, said decorating unit comprising a heated contact plate which is disposed to continuously urge the heat-transfer label into contact with the object throughout the period of decoration, and a conveying mechanism for advancing and supporting the object throughout the period of decoration.
Additional objects, as well as features and advantages, of the present invention will be set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice of the invention. In the description, reference is made to the accompanying drawings which form a part thereof and in which is shown by way of illustration a particular embodiment for practicing the invention. The embodiment will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.